1. Field of the Invention
The present invention generally relates to lined conduits. The present invention generally relates to a lined conduit formed by decorrugating a corrugated liner inside the conduit. The present invention also generally relates to an apparatus and method for forming a lined conduit by decorrugating a corrugated liner after the liner has been placed in the conduit.
2. Description of Related Art
The use of conduits, such as tubes and pipe, is well known. For example, elongated hollow tubes may be used as heat exchange tubes. The use of tubes in heat exchangers is disclosed in various U.S. patents, including U.S. Pat. No. 2,365,688 to Dewey; U.S. Pat. No. 2,342,117 to Brown et al.; U.S. Pat. No. 2,499,901 to Brown; U.S. Pat. No. 2,797,554 to Donovan; and U.S. Pat. No. 4,162,702 to Andersson, all of which are incorporated by reference as if fully set forth herein.
In some applications, such as tube-in-shell type heat exchangers, tubes having a non-uniform outer surface have been proposed. For example, in U.S. Pat. Nos. 5,251,693 and 5,311,661 to Zifferer, both of which are incorporated by reference as if fully set forth herein, a heat exchange tube having a portion that includes corrugations is described. U.S. Pat. No. 4,377,083 to Shepherd; U.S. Pat. No. 4,514,997 to Zifferer; U.S. Pat. No. 2,110,965 to Singer; U.S. Pat. No. 2,378,729 to Schmidt; and U.S. Pat. No. 4,383,429 to Ceccacci, all of which are incorporated by reference as if fully set forth herein, also describe modifications of cross-sectional shape and/or area of conduits. U.S. Pat. No. 5,016,806 to Yapp et al., which is incorporated by reference as if fully set forth herein, describes the use of rollers to impart a desired shape to a tubular member.
Conduits may be formed of many different materials. Some conduits may be made of materials that are relatively soft (e.g., copper or aluminum). Wall thickness of some conduits may be relatively thin. A conduit made of a relatively soft material and/or a conduit having a relatively thin wall thickness may be corrugated using blades to press indentions in the conduit. Some conduits may be made of relative hard materials (e.g., carbon steel, stainless steel, titanium). Some conduits may have relatively a relative large wall thickness. The use of blades to form a corrugated conduit from a relatively hard material and/or from a conduit having a relatively large wall thickness may be difficult.
A pointing device may be used to form a conduit with a reduced diameter end. U.S. Pat. No. 5,311,661 to Zifferer, which is incorporated by reference as if fully set forth herein, describes a pointing device for forming a reduced diameter end portion in a conduit.
Lined conduits may be used in a variety of environments to inhibit corrosion and/or abrasion of a conduit by material flowing through the conduit. U.S. Pat. No. 2,982,360 to Morton, which is incorporated by reference herein, describes providing a metal liner in combination with steel oil and/or gas well tubing such that the steel tubing will not be subject to hydrogen and stress-corrosion cracking. U.S. Pat. No. 6,354,373 to Vercaemer et al., which is incorporated by reference herein, describes an expandable tubing for a well bore hole in which selected length portions are weakened by a slot configuration to obtain predetermined expansion characteristics. U.S. Pat. No. 4,865,127 to Koster, which is incorporated by reference herein, describes a method and apparatus for relining bores, such as oil wells, using multiple layers of spiral wrapped, resilient lining material which expands to form a continuous liner for the bore. U.S. Pat. No. 5,390,742 to Dines et al., which is incorporated by reference herein, describes a specially configured tubular nipple structure that may be coaxially placed in a subterranean well flow conductor, and positioned therein to extend through a subsurface fluid production zone. U.S. Pat. No. 6,923,035 to Zifferer, which is incorporated by reference as if fully set forth herein, describes a method and apparatus for forming a corrugated conduit that may be inserted in a conduit and expanded to form a lined conduit.
U.S. Pat. No. 6,749,026 to Smith et al., which is incorporated by reference herein, describes a method of forming a downhole connection between tubular strings, including the step of crimping the tubular strings together. One of the tubular strings may be expanded outwardly within the other tubular string prior to the crimping step. U.S. Pat. No. 6,722,451 to Saugier, which is incorporated by reference herein, describes a method to deliver an expandable casing string to an uncased borehole coaxially upon a composite coiled tubing drilling string. Once the drilling operation is completed, the casing string is expanded by supplying pressure between the coaxially positioned strings to expand the casing string to the borehole.